Currently, many dual pawl ratchet mechanisms are known and used. Typically, these mechanisms are incorporated into handtools, such as wrenches and/or screwdrivers, or the like, so that there is a drive portion engageable with a working piece, for example, a bolt head. A first drive direction may be selected for the dual pawl ratchet mechanism so that use of the handtool provides torque when engaged with the bolt head and rotated in a first direction while slipping or ratcheting when rotated in a second direction. A second drive direction may be selected for the dual pawl ratchet mechanism that is opposite the first drive direction, and that provides torque and slip in the opposite direction.
In many environments in which these tools are used, it is common for the handtools to get dirty. The most common use of these handtools is in a work environment, such as a garage, or shop, or the like. For instance, using the handtool while working on an automobile in a garage or automotive bay often brings the handtool into contact with dirt, or oil and grease that are mixed with particulate dirt. The handtools, even when not being used, are usually stored in such environments where dirt may be floating in the air, only to settle on the handtool and become embedded in any grease or oil on the tool, as well as in any crevices in the tools. Cleaning of the handtools usually involves simply wiping the tool down.
To prevent ingress of dirt or particulate matter into the tools, attempts are made to seal the working components from the environment. However, the seals are located between working parts, so the seal itself may be exposed to the environment. Additionally, any cleaning product used on the tool must be done so carefully so as not to degrade the rubber or polymeric materials used for the seal. In some instances, a lubricating fluid may be retained by the seal, the fluid being particularly prone to degradation by contamination with particulate matter and/or by cleaning product solvents. Therefore, it is not uncommon to clean steel hand tools with a light oil, which serves to protect against rust but also promotes adhesion and ingress of the particulate matter.
In operating the reversible dual pawl mechanism, there is typically a manually actuable portion that effects the engagement of one pawl and the disengagement of a second pawl, the actuable portion being commonly referred to as a reversing lever. The drive direction for the drive portion is dependent on which of the two pawls is engaged.
The reversing lever is carried on a ratchet head or body and is movable relative thereto. Preferably, a seal is provided between the reversing lever and the ratchet head to prevent or impede ingress of particulate matter into the ratchet head where the matter could harm, ruin, or impede the proper operation of the handtool. However, the reversing lever is assembled essentially onto an outer side of the ratchet head (or in recess thereof) so that the seal is located between the bottom of the reversing lever or around its periphery. This has proved to be a less-than perfect seal for preventing ingress of matter or contaminants.
The reversing lever is typically rotated about an axis that is generally perpendicular to a face or side of the ratchet head to engage and dis-engage the pawls and, thus, to select the drive direction. The axis of rotation for the reversing lever is generally parallel to the axis of rotation of drive portion that provides the torque.
One of the problems with these handtools is the amount of rotation of the reversing lever. It is not uncommon to provide a spring and ball assembly, the spring biasing the ball into a detent, for defining the positions for the reversing lever. If the ball and detent cooperation is significant (such as due to a deep detent and spring with a high spring constant), the detent and ball can become worn or damage. On the other hand, if the cooperation is slight, the mechanism may not provide a clear tactile indication of reaching a selected position and/or may permit accidental shifting from the selected position, again leading to damage.
Accordingly, there has been a need for an improved dual pawl mechanism and reversing method.